California utilities and their consumer-facing vendors are leading the support for the White House’s Green Button initiative, but many more companies and utilities are joining the push.

Itron, Silver Spring Networks and Oracle all announced their support for the Green Button on Thursday. It is no surprise, since many of the companies’ utility clients have also committed to using Green Button. The White House announced on Thursday that another nine utilities, which collectively serve 15 million households, will support the Green Button.

Some of the largest utilities in the U.S. make up the list of new supporters, including American Electric Power, Austin Energy, Baltimore Gas & Electric, CenterPoint, Commonwealth Edison, NSTAR, Peco, Reliant and Virginia Dominion Power.

The Green Button, which was announced last fall, is a feature that allows residential and commercial customers to download detailed energy-use information in a standardized format to better manage electricity consumption and cost.

It’s no surprise to find that the largest vendors are following the largest utilities with their commitment to the project. Silver Spring Networks, for instance, will deploy its smart grid platform to four million homes and businesses in ComEd’s territory.

The utility is also working with Tendril, however, which was another early Green Button supporter. Not only is Tendril supporting the Green Button on its smart energy management platform, but it also has an application gallery where customers can choose to import their energy data and run it through different apps to understand and manage their energy in different ways.

Oracle is another vendor that works with SDG&E and Pacific Gas & Electric and which also announced its participation in the Green Button on Thursday. Although all of the companies have technology that touches the customer in different ways, it will only be one web portal that is presented to the customer by the utility.

Becoming the Green Button and customer engagement platform for any major utility will likely be about what options are offered on top of the basic Green Button functionality. Opower, like Tendril, also runs a platform that delivers Green Button data to PG&E customers and is developing more apps, including a Facebook app, to let customers crunch and share their data. On the commercial side, the small and medium commercial market is largely underserved and poorly understood. Tailoring a solution for those markets via apps that sit on top of the Green Button could be one way for vendors to differentiate themselves in a busy market.

If the government can finalize the standard for the Green Button, it will help to open it up to creative developers who can create meaningful and engaging apps for everyone from the average homeowner to a professional facility manager.

Currently, the Green Button system is based on a developing standard called Open Automated Data Exchange. The particular standard for that common format was finalized in a 1.0 version in October, and the federal government wants to make it a national smart grid standard. To encourage apps, PG&E just announced it is part of a $100,000 Green Button apps contest in partnership with the U.S. Department of Energy and Itron for developers that can spur the adoption of the Green Button. The winners will be announced in May.

California was the natural place for the initial Green Button adoption, given the state’s aggressive smart grid and renewable energy plans. But Thursday’s announcement shows that the appeal is far wider than the West Coast. Baltimore Gas & Electric has just begun a large smart meter implementation, and ComEd will also connect millions of homes and businesses.

Texas is another interesting market, because it’s deregulated, and some of the state’s largest electricity retailers and delivery companies have already committed to the Green Button.

Although Texas and California will be the leaders, the proliferation of utilities that are on board, and their vendors vying for a piece of the action, are early indications that this is really just the beginning of what the Green Button could achieve.